Grain scouring and polishing machine



C. C. MARSTON GRAIN SCOURING AND POLISHING MACHINE HVYE N76 R cwnvanca C. MflRsmAC ITOR/VEY Filed Jan. 2, 1954 Patented May 19, 1936 UNITED STATES PATENT OFFICE GRAIN SCOURING AND POLISHING MACHINE Candace Charles Marston, Bungay, England 4 Claims. (01. 83-37) This invention concerns improvements in or relating to scouring and polishing machines for grain and the like and more particularly to the type of scouring and polishing machine wherein the material to be treated is fed through a central perture so as to pass between two: horizontal relatively rotatable surfaces, the upper surface being in the form of a brush secured to or forming part of a disc, the nether surface being a 19 complementary disc or table; in this type of machine one or more methods are provided for the removal of scourings or refuse.

In machines of this type used hitherto, the treatment of the grain and its passage through and ejection from the machine by centrifugal action required the brush disc to be rotated at a high speed and to be pressed hard onto the grain so that considerable power is required, the machine, in particular the brush, quickly deteriorating due to excessive wear, and the grain itself being liable to more or less serious damage,

The object of this invention is to provide means whereby the forces, which can be brou t into being when machines of this type are in opera- 2 tion, are more effectively produced and utilized in conjunction with an additional force due to the incorporation of a specially arranged and constructed brush which forms a particular part of the invention, so that the necessary opera n 39 in the treatment of the grain or like material, its passage through and ejection from the machine, and the separation and collection of scourings and the like, are carried out more effectively than hitherto. Moreover, the invention permits great- 35 ly increased flexibility with regard to mechanical speed of operation in relation to the motive power required, the quantity of material treated, and the resultant quality of the product, a high degree of overall efficiency being thus obtained.

40 To this end, according to the present invention the horizontal brush, mounted over the nether surface on a common vertical axis provided with means to cause relative rotation therebetween,

5 has its bristles arranged so as to form a plurality of channels (either completely devoid of bristles or having shorter bristles than the main body) disposed tangentially to a circle co-axial with the brush. Generally it will be the brush that 0 rotates and the nether disc stationary, but modifications are described later. Other features which are advantageously employed will be apparent as the description develops.

One form of the invention is described in 55 greater detail in the following statement and 'tions being in the form of long narrow slots of with reference to the drawing attached hereto, wherein:

Figure 1 shows a cross section of the machine in elevation;

Figure 2 shows a plan of the machine with 5 covers removed and partly broken away to show the brush;

Figure 3 is a view to a smaller scale hereinafter referred to;

Figure 4 shows one way of perforating the 10 nether disc.

A flat annular ring or horizontal table I is made with a ring of discharge openings or slots 2 beneath which is fitted an annular collecting trough 3 by means of which the grain is collected 5 and fed by gravity to a discharge opening 4. In a preferred form of the invention, instead of the collecting trough there are one or more slots each fitted with a separate discharge spout, the

grain being swept into them by a brush or plate 21;

carried by the rotating brush.

Above the table I is a circular casing 5, a main cover plate 6 and a subsidiary or feed cover plate 1. Below the table is a circular tray or scourings hopper 8 made with one or more discharge openings or slots 9 beneath which is fitted a discharge spout or spouts, this spout having connected to it any suitable aspirating device so that a current of air can be drawn through the machine and at the same time convey the scourings; or 30, the aspirating device can be connected to an additional opening in the hopper and the scourings removed by way of an intermittent or continuously operating discharge valve connected to the discharge spout or spouts. Internally, covering the central space in the table and dividing the interior of the machine into two comp-artments is the nether disc in which, in the embodiment, is a perforated plate or disc, the perforathe type shown in Fig 4.

At the circumference of the perforated plate is a raised rim or fence I I thus providing a shallow saucer-like central area and surrounding it the slotted channel l2.

Through the machine is a vertical driving shaft I3 and secured to that part of the shaft in the scourings hopper is a boss carrying two radial arms l4 arranged as shown in Fig. 3, one carrying a metal or brush cleaner to sweep the perforated plate, the other to sweep scourings from the hopper into the discharge openings, which are also shown in Figure 3. Secured to that part of the shaft in the compartment above the per- 55 forated plate is a boss extending from which are radial arms forming part of a feed ring I5 and a surrounding flange or gallery to which is secured a brush disc or plate l6.

Secured to the undersurface of the brush plate is a brush I! the construction of which is a particular feature of the machine, in that the tufts of bristles, or other material of which it may be constituted, are disposed or grouped together in separate sections so as to provide, firstly, a circular blank area or feed space l8 co-axial with the feed ring, and secondly, a number of channels l9 diverging outwards from the feed space along lines which are tangential to a circle 20 c0- axial with the feed ring and brush plate, the channels being spaces which are either devoid of bristles or in which the bristles are very short by comparison with those of the brush sections.

Around the brush plate is a flanged metal band 21 the skirt of which extends downwards to deflect centrifugally displaced air towards the perforated plate and at the same time to ensure that the grain accumulating at the periphery of the brush is prevented from damaging the circumferential bristles of the brush.

The diameter of the feed space [8 and the channel circle 28 together with the dimensions of the channels and the brush are arranged according to the kind of grain or like material to be treated and the desired quantitative capacity of the machine.

When the machine is in operation, and the brush is being rotated by the driving shaft, the grain is fed by way of the feed ring to the feed space whence it passes between the brush and nether plate where it is scoured, the scour ings or refuse passing into the scourings hopper, the operation being described as follows:

The grain is conveyed from the feed space by the force due to feed flow and centrifugal action into the entrances of the channels and between the brush face and the perforated plate. As the grain passes beneath any section of the brush, its outward or centrifugal movement is diminished and it is swept around the perforated plate; but due to friction between grain and plate, the brush overrides and brushes the grain, so that it is eventually uncovered by that section of the brush under which it is being secured and polished. In effect, the grain passes into the comparative freedom of the channel next following, and under the continued influence of centrifugal force, unopposed or less restrained momentarily by the bristles, moves outwards along the channel for a short distance before passing under the leading edge of the next section of the brush; this sequence and combination of outward and circular movement ensures a gradual and evenly distributed flow of grain between the brush and the plate.

On being ejected from the brush, the movement of the grain into the annular slotted trough, and thence to the discharge spout or spouts is impeded by the raised rim or fence and the slight congestion of grain thus caused, in conjunction with the metal skirt of the brush plate forms an air seal and ensures that the air displaced by the rotation of the brush and by the suction device connected to the scourings hopper, directs the draught by way of the feed space and through the perforations in the plate.

For satisfactory and efficient scouring and polishing it is a particular feature of this invention that the specially constructed brush enables the clearance between the brush face and the perforated plate to be arranged so that the tips of the bristles bear only lightly upon the grain. This light contact allows the individual grains to be rolled or turned about their axes, and their entire surfaces to be scoured and polished by the tips of the bristles against the restraint and scouring and polishingaction caused by friction of the individual grains with one another and with the edges of the slots in the plate, augmentedby the holding effect of the air draught through the slots.

The speed of rotation of the brush and the motive power required to overcome the total resistance to rotation is reduced, therefore, to a minimum compatible with satisfactory and efficient scouring of the grain. A brush speed as low as 60 revolutions per minute has been found to be satisfactory and 270 revolutions per minute need not be exceeded in any case due to the factors above mentioned, in particular, the special brush which enables a satisfactory flow to be maintained by the comparatively low centrifugal force available within the speed range indicated.

Another form of the invention is that in which the perforated plate, as described above, is replaced by a plate the surface of which is not, or is only partly perforated, the whole or the remainder of its surface being either partly or entirely smooth, indented, embossed, fluted or abrasively formed. When non-perforated surface is used, scourings are removed by separate treatment after the grain has been discharged from the machine.

Yet another form of the invention is that in which the brush and the plate both rotate round a vertical axis, means being provided whereby the mechanical speed of the one may be made greater or less than that of the other, so that, for instance, when both surfaces are rotating in the same direction, the force due to centrifugal action can be increased or decreased independently of the relative speed between brush and plate, i. e. the scouring action, thus enabling a high degree of flexibility of operation and control to be obtained.

I claim:

1. A grain scouring and polishing machine comprising a horizontally disposed perforated plate, a rotatable brush disposed horizontally above said plate and having downwardly directed bristles for cooperation with said plate, said brush having a central grain feed opening and further having channels formed through the bristles and extending from the central feed opening to the periphery of the brush tangentially to a circle coaxial with the feed opening, a dam element surrounding the brush and having its inner face sloping upwardly and outwardly from the top of the perforated plate, and a flange carried by the brush and surrounding the brush bristles, said flange being disposed inwardly of said dam element and having its lower edge spaced from the upper face of the perforated plate.

2. A grain scouring and polishing machine comprising a horizontally disposed perforated plate, a rotatable brush disposed horizontally above said plate and having downwardly directed bristles for cooperation with said plate, said brush having a central grain feed opening and further having channels formed through the bristles and extending from the central feed opening to the periphery of the brush tangentially to a circle coaxial with the feed opening, a dam element rising from the perforated plate in surrounding relationship to the brush, and a flange carried by the brush in surrounding relationship to the brush bristles, said flange being spaced inwardly from said dam element and having its lower edge spaced from the upper face of the perforated plate to provide in cooperation with the plate and dam element a passageway for the escape of grain from between the brush and the plate.

3. A grain scouring and polishing machine as set forth in claim 2 including a scourings receiving hopper disposed below the perforated plate, and a suction conduit connected with said hopper.

4. A grain scouring and polishing machine as set forth in claim 2 including a scourings receiving hopper below the perforated plate, and a pair of brushes within said hopper disposed, one to brush the bottom of the plate and the other to brush the bottom of the hopper.

CAN'DACE CHARLES MARSTON. 

